RingMad wondered how I achieved the fading on the audio for the Enneatronic Spectralizer so here's
the schematic and some extra info for those interested.

THE ENNEATRONIC SPECTRALIZER

The Enneatronic Spectralizer is a drone box containing 9 tunable squarewave oscillators with a
simple, 1 transistor, VCA section to fade the sound of each oscillator in and out. The same oscillators that
control the VCA's also control 42(!) LED's, arranged in such a way that it creates a constantly changing
display of symmetrical patterns.

thanks for posting that pic richardc64

The oscillators are all made with a CD40106 (3 chips in total) combined with some resistors, capacitors and
transistors to create the fading effect for both sound and LED's. Values were selected by means of experimentation
to get the result I was happy with. So if you want to use the circuit with a different supply voltage you'll probably
have to change some values. The fading of the LED's also varies with the kind of LED's used, so this will need
some experimentation aswell.

Each group of 3 oscillators (build around a single CD40106) also has a switch to turn the sound off. This makes
tuning a bit easier but can also be used to switch between differently tuned drones. The tuning itself is done
with a 47K pot (fine) in series with a 250K trimpot for pretuning (coarse). Originally the circuit was made with
just the 250K trimpots, but it was difficult to tune them pecisely so I added the 47k pots in series and
pretuned them to a low, mid and high section.

The sounds of the oscillators are mixed together with an opamp and then send out to a jack, which is wired up
in such a way that it can also be used as an EFX Send/Return for the build in amplifier. The amplifier itself is a
very basic LM386 setup. The 65Ω speaker was just something I had laying around that was small enough, so it
doesn't have to be 65Ω.

some extra info on the display:
- directly in front of the LED's there's a layer of frosted plastic to diffuse the light a bit. (cut from a box that came with some VHS tapes).
- on top of this is a blue lighting filter to dim the lights. (42 bright green LED's produce a lot of light! )
- followed by a green lighting filter which together with the blue creates a very nice shade of green.
- this is covered with a piece of perspex to protect it which also functions as a mirror if you turn the LED's off (bonus effect).

because there is some space between the LED's and the plastic it creates a sort of 3D effect were the brighter LED's
seem closer then ones that are dimmed. (I added a photo which shows this a bit)

Wow, PHOBoS, thanks for all that documentation! So very generous of your time.

And let me say, because I'm feeling it strongly right now, that I love these DIY forums here on e-m... so inspirational and educational and fun and it keeps one going knowing there are other people spending hours soldering up crazy projects that most people would not understand the point of.

Thank you for sharing this. It is helpful as I have been working on a vca type of circuit for my Lunetta and this is proving to be helpful in getting points that I was struggling with working to my liking.

Very cool housing you have created on the last few projects, the LED display on this one makes it that much more interesting.

I forgot to mention, it's like IT's "deadlights", once you watch them it's hard to look away
(and it might drive you insane, but it's probably too late for that anyway)

It reminds me of the Neural Neutralizer in the Dagger of the Mind episode of Star Trek (how much of a nerd does that make me?). Hope that it doesn't have the same effect... I really like the sound and look of this. Another thing to add to my list of ideas to try - I don't know if I'll live long enough to get through that list.

dirtyworm wrote:

Thank you for sharing this. It is helpful as I have been working on a vca type of circuit...

Id love to know/see more on how you layed out and wired up the LEDS to the VCAs. It truly is a fantastic effect. The orientation and fade rate is just superb.

I think I lost the PCB layout for the LED's in a crash else I could post that. but I can tell you that the LED's are wired
in groups of 3 (in the center) or 6.
I should have made a photo before I put the cover in front of the LED's, I'll try to take a photo some other time with the cover.
Actually if you pause the video somewhere around 10-12 seconds you can see the layout, allthough a bit blurred.

here's the first version, with a different layout and no sound. (and cheap chinese LED's )

and here is another recording of the Enneatronic Spectralizer this time droning together with a LED fan

Biyi showed interest in making a spectralizer and was asking for a layout and more info so I'll just post that here.
First thing is how the LED's are wired up.
I just soldered them on a piece of perfboard and then soldered wires to the legs to connect everything together.
Here's the layout and a coloured map to show which LED's are wired together and to what knob they are linked.

Here's the original perfboard layout for the modules
I made 3 of those and later added the 47K pots. I soldered those to the edge of the boards as can be seen on this photo:
(I had to cut a small part off to get them in the box)
The 47K pots are connected instead of the connections between the 250K trimpots and 10K resistors using some wires.

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Enneatronic Spectralizer module layout (full)

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Enneatronic Spectralizer module layout (top)

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Enneatronic Spectralizer - 08.jpg

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Enneatronic Spectralizerthe green wires are the connections to the 47K pots.

Hi Phobos,thank you very much for all this information!!!! we certainly encourage everyone to help build this fantastic machine.

You really are the master! I expect good hours of entertainment and fun ...

Question: what is the resistor 1k and cap value and what is red circle on top of the circuit? its a led? i think its a led red and the cap its a 100nf on schema..ok?
Thanks again !!! when I have something done .. I will keep you informed.

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What is the cap value and what is the red circle?led?

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Last edited by Biyi on Mon Jun 02, 2014 10:40 am; edited 1 time in total

The cap is a decoupling cap (I usually don't label those, nor draw them in schematics ) so 100nF would be fine.
And the circle is indeed a (3mm) LED, which simple shows if the PCB is powered, so you can leave that and the 1K resistor off the board.

Hello everyone , this is an approximation of the Phobos Eneatronic Spectralizer. PCBs in pdf, one is the actual view and another the pcb.
I also included the power supply and amplification.
I still have not done the tests to verify them .. I hope to soon! I am now trying to do the pcb for leds ..
Thank you all ..

Phobos I would like to change the name Eneatronic by ....Psychomanteum..
surely add a low pass filter..also.

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